Direction api: check if a place falls in the route path between 2 places

Question

I am using Google Direction API to plot the route path between 2 places A and B. I am able to do this. Now, I have a requirement to check if given a place C falls in the route path of A and B.

Here is the snapshot of the route path that I have generated from my code.

Here is the corresponding code:

function initialize() {
                var input = document.getElementById('searchTextFieldSource');
                var input1 = document.getElementById('searchTextFieldDestination');

                var autocomplete = new google.maps.places.Autocomplete(input);
                var autocomplete1 = new google.maps.places.Autocomplete(input1);
                google.maps.event.addListener(autocomplete1, 'place_changed', function () {
                    var place = autocomplete.getPlace();
                    document.getElementById('city1').value = place.name;
                    var place1Lat = place.geometry.location.lat();
                    var place1Lng = place.geometry.location.lng();
                    document.getElementById('cityLat1').value = place1Lat;
                    document.getElementById('cityLng1').value = place1Lng;

                    var obj = new Object();
                    obj.city =place.name;
                    obj.latitude = place.geometry.location.lat();
                    obj.longitude = place.geometry.location.lng();
                    locations.push(obj);


                    var place2 = autocomplete1.getPlace();
                    document.getElementById('city2').value = place2.name;
                    var place2Lat = place2.geometry.location.lat();
                    var place2Lng = place2.geometry.location.lng();
                    document.getElementById('cityLat2').value = place2Lat;
                    document.getElementById('cityLng2').value = place2Lng;

                    var obj = new Object();
                    obj.city = place2.name;
                    obj.latitude = place2.geometry.location.lat();
                    obj.longitude = place2.geometry.location.lng();
                    locations.push(obj);

                    directionsDisplay = new google.maps.DirectionsRenderer();
                    var startPlace = new google.maps.LatLng(place1Lat, place1Lng);

                    var mapOptions = {
                        zoom:7,
                        center: startPlace
                    }

                    var map = new google.maps.Map(document.getElementById('map'), mapOptions);
                    directionsDisplay.setMap(map);
                    //refreshMap(locations);

                    var start = $("#city1").val();
                    var end = $("#city2").val();
                    var request = {
                          origin:start,
                          destination:end,
                          travelMode: google.maps.TravelMode.DRIVING
                    };
                    directionsService.route(request, function(response, status) {
                        if (status == google.maps.DirectionsStatus.OK) {
                          directionsDisplay.setDirections(response);
                        }
                    });
                });
            }

How can I go about it?

Compilation

I don't see "place C" in your code. One option is to use RouteBoxer to determine a reasonable bounds for your route. If the intermediate point is contained by those bounds, that might be good enough, otherwise you can perform further tests (like distance from the route polyline. See this similar question (which doesn't have an answer either) – Lorgnon

Gas Stations along (within ~0.25 miles of) your route – Lorgnon

@Lorgnon - That's not quite the same. In this case, you already know the position of place C. RouteBoxer would be overkill for this problem. – Astonishing

Yes. It would be computation intensive to use RouteBoxer for the case when C is known. – Compilation

Answer 1

You can use the geometry library that (you can request with google maps by changing your script src to https://maps.googleapis.com/maps/api/js?sensor=false&libraries=geometry) and use isLocationOnEdge and use the LatLng of point C and the polyline that is returned from the DirectionsService.

https://developers.google.com/maps/documentation/javascript/geometry#isLocationOnEdge

Then again, point C could ALWAYS be on the way between A and B if you added it as a waypoint, so determining if point C is "on the way" is actually a bit of a tricky concept - how far out of the way is too far for it to not be "on the way"?

Astonishing

So using isLocationOnEdge, I can only find the points on the polyline right? Not the points which may be near the polyline(like say 0.5 kms from the polyline). – Compilation

Look at the link to the documentation. isLocationOnEdge takes an optional third argument - tolerance which is the number of degrees you specify for the point to still be considered on the edge - i.e. for the function to return true It's worth pointing out that the same number of degrees will give you a different real distance (in km or mi) depending on the exact latitude or longitude. – Astonishing

Any idea? how to do it with php and my sql. i am having a multidimensional array and each object inside it has {lat,lng}. i want to check if any one or more points from the multidimensional array are lying on the current route – Equable

@KamleshJha Did you completed your requirement work? I have the same problem.. plz reply. – Gobioid